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Characterization of the limit load in the case of an unbounded elastic convex

Adnene Elyacoubi, Taieb Hadhri (2005)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

In this work we consider a solid body Ω 3 constituted by a nonhomogeneous elastoplastic material, submitted to a density of body forces λ f and a density of forces λ g acting on the boundary where the real λ is the loading parameter. The problem is to determine, in the case of an unbounded convex of elasticity, the Limit load denoted by λ ¯ beyond which there is a break of the structure. The case of a bounded convex of elasticity is done in [El-Fekih and Hadhri, RAIRO: Modél. Math. Anal. Numér. 29 (1995)...

Characterization of the limit load in the case of an unbounded elastic convex

Adnene Elyacoubi, Taieb Hadhri (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

In this work we consider a solid body Ω 3 constituted by a nonhomogeneous elastoplastic material, submitted to a density of body forces λ f and a density of forces λ g acting on the boundary where the real λ is the loading parameter. The problem is to determine, in the case of an unbounded convex of elasticity, the Limit load denoted by λ ¯ beyond which there is a break of the structure. The case of a bounded convex of elasticity is done in [El-Fekih and Hadhri, RAIRO: Modél. Math. Anal. Numér. 29 (1995)...

Curl bounds grad on SO(3)

Ingo Münch, Patrizio Neff (2008)

ESAIM: Control, Optimisation and Calculus of Variations

Let F p GL ( 3 ) be the plastic deformation from the multiplicative decomposition in elasto-plasticity. We show that the geometric dislocation density tensor of Gurtin in the form Curl [ F p ] · ( F p ) T applied to rotations controls the gradient in the sense that pointwise R C 1 ( 3 , SO ( 3 ) ) : Curl [ R ] · R T 𝕄 3 × 3 2 1 2 D R 27 2 . This result complements rigidity results [Friesecke, James and Müller, Comme Pure Appl. Math. 55 (2002) 1461–1506; John, Comme Pure Appl. Math. 14 (1961) 391–413; Reshetnyak, Siberian Math. J. 8 (1967) 631–653)] as well as an associated linearized theorem...

Curl bounds Grad on SO(3)

Patrizio Neff, Ingo Münch (2010)

ESAIM: Control, Optimisation and Calculus of Variations

Let F p GL ( 3 ) be the plastic deformation from the multiplicative decomposition in elasto-plasticity. We show that the geometric dislocation density tensor of Gurtin in the form Curl [ F p ] · ( F p ) T applied to rotations controls the gradient in the sense that pointwise R C 1 ( 3 , SO ( 3 ) ) : Curl [ R ] · R T 𝕄 3 × 3 2 1 2 D R 27 2 . This result complements rigidity results [Friesecke, James and Müller, Comme Pure Appl. Math.55 (2002) 1461–1506; John, Comme Pure Appl. Math.14 (1961) 391–413; Reshetnyak, Siberian Math. J.8 (1967) 631–653)] as well as an associated linearized theorem saying...

Determination of creep, fatigue and activation energy from constant strain-rate experiments

Michele Caputo (1982)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Si interpretano i risultati degli esperimenti fatti su mezzi anelastici mediante applicazione di deformazioni crescenti linearmente nel tempo. Si trova che dai risultati di questi esperimenti, si può risalire alla funzione di creep che viene determinata con tre diversi modelli di approssimazione. Si trova inoltre che per decidere sul comportamento a lungo termine dei materiali sono necessari esperimenti a più lungo termine di quelli fatti. Si dimostra poi che le relazioni classiche che rappresentano...

Dislocation dynamics - analytical description of the interaction force between dipolar loops

Vojtěch Minárik, Jan Kratochvíl (2007)

Kybernetika

The interaction between dislocation dipolar loops plays an important role in the computation of the dislocation dynamics. The analytical form of the interaction force between two loops derived in the present paper from Kroupa’s formula of the stress field generated by a single dipolar loop allows for faster computation.

Dynamic analysis of viscous material models

Trcala, Miroslav, Němec, Ivan, Vaněčková, Adéla, Hokeš, Filip (2021)

Programs and Algorithms of Numerical Mathematics

The article deals with the analysis of the dynamic behavior of a~concrete structural element during fast dynamic processes. The constitutive material model must be chosen appropriately so that it takes material viscosity into account when describing the behavior of material. In this analysis, it is necessary to use fairly complex viscous material models which can affect, for example, vibration damping and the dependence of strength or even of the entire stress-strain curve on the strain rate. These...

Dynamic Damping - Comparison of different concepts from the point of view of their physical nature and effects on civil engineering structures

Němec, Ivan, Trcala, Miroslav, Vaněčková, Adéla, Rek, Václav (2019)

Programs and Algorithms of Numerical Mathematics

Sources of dynamic damping may be various. Mostly, the damping is implemented into calculations in a form of introduction of damping forces, as a product of the velocity vector and the damping matrix in an equation of motion. In practice, the damping matrix is usually assumed to be a linear combination of the mass matrix and the stiffness matrix (so called Rayleigh’s damping). This kind of damping primarily assumes the external environment viscosity as the source of damping, even though the part...

Dynamical model of viscoplasticity

Kisiel, Konrad (2017)

Proceedings of Equadiff 14

This paper discusses the existence theory to dynamical model of viscoplasticity and show possibility to obtain existence of solution without assuming weak safe-load condition.

Dynamics of shock waves in elastic-plastic solids

N. Favrie, S. Gavrilyuk (2011)

ESAIM: Proceedings

The Maxwell type elastic-plastic solids are characterized by decaying the absolute values of the principal components of the deviatoric part of the stress tensor during the plastic relaxation step. We propose a mathematical formulation of such a model which is compatible with the von Mises criterion of plasticity. Numerical examples show the ability of the model to deal with complex physical phenomena.

Efficient inexact Newton-like methods with application to problems of the deformation theory of plasticity

Radim Blaheta, Roman Kohut (1993)

Applications of Mathematics

Newton-like methods are considered with inexact correction computed by some inner iterative method. Composite iterative methods of this type are applied to the solution of nonlinear systems arising from the solution of nonlinear elliptic boundary value problems. Two main quastions are studied in this paper: the convergence of the inexact Newton-like methods and the efficient control of accuracy in computation of the inexact correction. Numerical experiments show the efficiency of the suggested composite...

Error estimates of an iterative method for a quasistatic elastic-visco-plastic problem

Ioan Rosca, Mircea Sofonea (1994)

Applications of Mathematics

This paper deals with an initial and boundary value problem describing the quasistatic evolution of rate-type viscoplastic materials. Using a fixed point property, an iterative method in the study of this problem is proposed. A concrete algorithm as well as some numerical results in the one-dimensional case are also presented.

Estensione a leggi costitutive a variabili interne dei teoremi di inadattamento in dinamica strutturale elastoplastica

Alberto Corigliano, Claudia Comi (1990)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Si considera il problema del mancato adattamento in campo dinamico per strutture elasto-plastiche incrudenti. Si dimostrano una condizione necessaria ed una sufficiente per il verificarsi di fenomeni di inadattamento (plasticità alternata o collasso incrementale) estendendo risultati precedenti ad un'ampia classe di modelli costitutivi a variabili interne in grado di rappresentare comportamenti incrudenti non lineari.

Estensione di un teorema sull'adattamento in dinamica elasto-plastica

Claudia Comi, Alberto Corigliano (1990)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Nell'articolo si tratta il problema dell'adattamento in dinamica elasto-plastica. La trattazione è fondata sulle seguenti basi: si adotta un legame costitutivo elasto-plastico di notevole generalità, basato su di una formulazione a variabili interne in grado di descrivere un comportamento incrudente genericamente non lineare; si fa riferimento ad un modello strutturale discreto, descritto mediante variabili generalizzate. I contributi presentati si possono così riassumere: si estendono risultati...

Estimation of EDZ zones in great depths by elastic-plastic models

Sysala, Stanislav (2023)

Programs and Algorithms of Numerical Mathematics

This contribution is devoted to modeling damage zones caused by the excavation of tunnels and boreholes (EDZ zones) in connection with the issue of deep storage of spent nuclear fuel in crystalline rocks. In particular, elastic-plastic models with Mohr-Coulomb or Hoek-Brown yield criteria are considered. Selected details of the numerical solution to the corresponding problems are mentioned. Possibilities of elastic and elastic-plastic approaches are illustrated by a numerical example.

Currently displaying 21 – 40 of 151